func main() {
	var err error
	var challenge []byte
	var response []byte
	var group *bbssig.Group = new(bbssig.Group)
	var gfile *os.File
	gfile, err = os.Open(os.Args[3])
	if err != nil {
		log.Fatal(err)
	}
	var ghandle = bufio.NewReader(gfile)
	{
		var gb = basepack.Unpack(ghandle)
		var success bool
		_, success = group.Unmarshal(gb)
		if !success {
			log.Fatal("Unable to unmarshal public key")
		}
	}
	challenge, err = base64.StdEncoding.DecodeString(os.Args[1])
	if err != nil {
		log.Fatal("Invalid challenge")
	}
	response, err = base64.StdEncoding.DecodeString(os.Args[2])
	if err != nil {
		log.Fatal("Invalid response")
	}
	if group.Verify(challenge, sha256.New(), response) {
		fmt.Printf("yes\n")
		os.Exit(0)
	} else {
		fmt.Printf("no\n")
		os.Exit(1)
	}
}

func main() {
	var err error
	var ofhandle *os.File
	ofhandle, err = os.Create(os.Args[1])
	if err != nil {
		log.Fatal(err)
	}
	var privhandle *os.File
	privhandle, err = os.Open(os.Args[2])
	if err != nil {
		log.Fatal(err)
	}
	var privreader *bufio.Reader
	privreader = bufio.NewReader(privhandle)
	var group *bbssig.Group = new(bbssig.Group)
	var privkey *bbssig.PrivateKey = new(bbssig.PrivateKey)
	var part *bbssig.MemberKey = new(bbssig.MemberKey)
	var randreader *os.File
	randreader, err = os.Open("/dev/random")
	if err != nil {
		log.Fatal(err)
	}
	var gb []byte
	{
		gb = basepack.Unpack(privreader)
		var success bool
		_, success = group.Unmarshal(gb)
		if !success {
			log.Fatal("Unable to unpack group data")
		}
		var pb = basepack.Unpack(privreader)
		_, success = privkey.Unmarshal(group, pb)
		if !success {
			log.Fatal("Unable to unpack private key")
		}
	}
	part, err = privkey.NewMember(randreader)
	if err != nil {
		log.Fatal(err)
	}
	{
		var partbyte = part.Marshal()
		objpack.PackGroup(ofhandle, part.Group)
		basepack.Packout(ofhandle, partbyte)
		fmt.Printf("Tag for part is ")
		basepack.Packout(os.Stdout, part.Tag())
	}
	ofhandle.Close()
	privhandle.Close()
	randreader.Close()
}

func UnPackPart(partreader *bufio.Reader, group *bbssig.Group,
	part *bbssig.MemberKey) {
	var gb = basepack.Unpack(partreader)
	var success bool
	_, success = group.Unmarshal(gb)
	if !success {
		log.Fatal("Unable to unpack group")
	}
	var mb = basepack.Unpack(partreader)
	_, success = part.Unmarshal(group, mb)
	if !success {
		log.Fatal("Unable to unpack part")
	}
}

func main() {
	var err error
	var group = new(bbssig.Group)
	var sk = new(bbssig.PrivateKey)
	var part = new(bbssig.MemberKey)
	var rev *bbssig.Revocation
	var revbyte []byte
	var partfile *os.File
	partfile, err = os.Open(os.Args[1])
	if err != nil {
		log.Fatal(err)
	}
	var privfile *os.File
	privfile, err = os.Open(os.Args[2])
	if err != nil {
		log.Fatal(err)
	}
	var partreader = bufio.NewReader(partfile)
	var privreader = bufio.NewReader(privfile)
	/* Now we have a detail, namely need to skip some stuff from
	the part file before we can use it. But first load the
	private key*/
	{
		var gb = basepack.Unpack(privreader)
		var success bool
		_, success = group.Unmarshal(gb)
		if !success {
			log.Fatal("Could not load key")
		}
		var sb = basepack.Unpack(privreader)
		_, success = sk.Unmarshal(group, sb)
		if !success {
			log.Fatal("Could not load private key")
		}
	}
	{
		var success bool
		basepack.Unpack(partreader) /*Skip first entry*/
		var memb = basepack.Unpack(partreader)
		_, success = part.Unmarshal(group, memb)
		if !success {
			log.Fatal("Part could not be upacked")
		}
	}
	rev = sk.GenerateRevocation(part)
	revbyte = rev.Marshal()
	fmt.Printf("The revokation string is %s\n",
		base64.StdEncoding.EncodeToString(revbyte))
}

func main() {
	var err error
	var group = new(bbssig.Group)
	var priv = new(bbssig.PrivateKey)
	var privhandle *os.File
	privhandle, err = os.Open(os.Args[2])
	if err != nil {
		log.Fatal(err)
	}
	var privreader *bufio.Reader
	privreader = bufio.NewReader(privhandle)
	{
		var gp []byte
		var success bool
		gp = basepack.Unpack(privreader)
		_, success = group.Unmarshal(gp)
		if !success {
			log.Fatal("Unable to read group data")
		}
		var pb []byte
		pb = basepack.Unpack(privreader)
		_, success = priv.Unmarshal(group, pb)
		if !success {
			log.Fatal("Unable to read private key")
		}
	}
	var sig []byte
	sig, err = base64.StdEncoding.DecodeString(os.Args[1])
	if err != nil {
		log.Fatal("Signature is invalid")
	}
	var tag []byte
	var success bool
	tag, success = priv.Open(sig)
	if !success {
		log.Fatal("Signature unknown")
	} else {
		fmt.Printf("The tag is %s\n", base64.StdEncoding.EncodeToString(tag))
	}
}

func (s *Server) revocation(from *[32]byte, signedRevocation *pond.SignedRevocation) *pond.Reply {
	account, ok := s.getAccount(from)
	if !ok {
		return &pond.Reply{Status: pond.Reply_NO_ACCOUNT.Enum()}
	}

	revocation, ok := new(bbssig.Revocation).Unmarshal(signedRevocation.Revocation.Revocation)
	if !ok {
		return &pond.Reply{Status: pond.Reply_CANNOT_PARSE_REVOCATION.Enum()}
	}

	// First check that the account doesn't have too many revocations
	// stored.

	revPath := account.RevocationPath()
	os.MkdirAll(revPath, 0777)

	revDir, err := os.Open(revPath)
	if err != nil {
		log.Printf("Failed to open %s: %s", revPath, err)
		return &pond.Reply{Status: pond.Reply_INTERNAL_ERROR.Enum()}
	}
	defer revDir.Close()

	ents, err := revDir.Readdir(0)
	if err != nil {
		log.Printf("Failed to read %s: %s", revDir, err)
		return &pond.Reply{Status: pond.Reply_INTERNAL_ERROR.Enum()}
	}

	if len(ents) > maxRevocations {
		// Delete the oldest revocation.
		names := make([]string, 0, len(ents))
		for _, ent := range ents {
			names = append(names, ent.Name())
		}
		sort.Strings(names)
		path := filepath.Join(revPath, names[0])
		if err := os.Remove(path); err != nil {
			log.Printf("Failed to remove %s: %s", path, err)
			return &pond.Reply{Status: pond.Reply_INTERNAL_ERROR.Enum()}
		}
	}

	path := filepath.Join(revPath, fmt.Sprintf("%08x", *signedRevocation.Revocation.Generation))
	revBytes, err := proto.Marshal(signedRevocation)
	if err != nil {
		log.Printf("Failed to serialise revocation: %s", err)
		return &pond.Reply{Status: pond.Reply_INTERNAL_ERROR.Enum()}
	}

	if err := ioutil.WriteFile(path, revBytes, 0666); err != nil {
		log.Printf("Failed to write revocation file: %s", err)
		return &pond.Reply{Status: pond.Reply_INTERNAL_ERROR.Enum()}
	}

	group := account.Group()
	if group == nil {
		return &pond.Reply{Status: pond.Reply_INTERNAL_ERROR.Enum()}
	}
	groupCopy, _ := new(bbssig.Group).Unmarshal(group.Marshal())
	groupCopy.Update(revocation)

	account.Lock()
	defer account.Unlock()

	account.group = groupCopy
	groupPath := filepath.Join(account.Path(), "group")
	if err := ioutil.WriteFile(groupPath, groupCopy.Marshal(), 0600); err != nil {
		log.Printf("failed to write group file: %s", err)
	}

	return nil
}

func PackGroup(out io.Writer, g *bbssig.Group) {
	var pub []byte
	pub = g.Marshal()
	basepack.Packout(out, pub)
}